International migration is increasingly important in shaping national population dynamics, both directly through adding or subtracting people, and indirectly, through the fertility of immigrants. International migrants rarely share the fertility characteristics of either origin or destination populations. However, the relationship between migration and fertility is little understood, especially that relating to refugee populations. This study examined the fertility differentials of one of the world"s largest refugee populations, the Afghans in Iran, in relation to the host population. Based on multivariate analysis, the study demonstrated that Afghan immigrants were moving from a high fertility regime to a low fertility regime. The findings suggest that fertility change among Afghans is associated with their adaptation to Iranian society. The role of education in mediating immigrant-native fertility differentials was also uncovered.